99e2a9f530 Remove unnecessary rustdocs (Tobin C. Harding)
Pull request description:
The `deprecated` attribute already fully explains the status of a deprecated function and the replacement - no need to repeat this.
ACKs for top commit:
apoelstra:
ACK 99e2a9f530eced69e9df1441e15d24e626974385; successfully ran local tests
Tree-SHA512: 133d41573a3ba97abf85100649c1e8dfe131521a627e0b7f1ab803845caf1c183b99488cb5d9f7e858cab1b35f8907a79b320ec01901b15fdd63d08f0bc1f87e